The present invention relates to screens for reproducing continuous-tone pictures of the kind having an equally-spaced screen structure and which is rotated from the direction of reproduction by 45.degree.. Such a screen will hereinafter be referred to as "of the kind described".
In reproduction technology, there are a multiplicity of known reproduction screens for continuous-tone pictures, and a method of reproduction which is frequently employed is to trace out the individual screen-dots at the time of reproduction by means of a light beam, the various screen dots which occur in the case of individual total values having been stored in a store in the form of digitally coded reproduction data and, when the picture is being reproduced, being called up from the store and reproduced again under the control of the control of the scanning process. This method is for example described in U.S. Pat. Spec. No. 3,688,033. In this specification, the reproduction process is described using the example of the reproduction of continuous-tone pictures by means of electronic photosetting apparatus. The method may however also be applied to so-called drum or flat-bed reproducing apparatus, and in this connection reference may for example be made to U.S. Pat. Spec. No. 3,725,574. Good results are achieved with the said method, but there are applications in which extremely high quality is required. It has been found, particularly when reproducing outlines, that the optimum standard of reproduction is not achieved, which is attributable to the physical distribution of the information within the screen dots reproduced. Therefore, with the known method, additional circuits must be provided to take into account the area surrounding a scanned dot, which involves additional complication.
It is an object of the invention therefore to provide an improved screen of the kind described.